Explore: Restricts query text edit toggle to metrics mode (#17921)

* Explore: Adds datasource plugin config option 'modesSupportingTextEdit'
This allows one to specify which modes support toggling query text edit on and off
Closes #17904

* Explore: Restricts query text edit toggle to metrics mode

public/app/features/explore/QueryRow.tsx

@@ -129,7 +129,8 @@ export class QueryRow extends PureComponent<QueryRowProps, QueryRowState> {
       queryErrors,
       mode,
     } = this.props;
-    const canToggleEditorModes = _.has(datasourceInstance, 'components.QueryCtrl.prototype.toggleEditorMode');
+    const canToggleEditorModes =
+      mode === ExploreMode.Metrics && _.has(datasourceInstance, 'components.QueryCtrl.prototype.toggleEditorMode');
     let QueryField;
 
     if (mode === ExploreMode.Metrics && datasourceInstance.components.ExploreMetricsQueryField) {